---
title: 'Data validation'
sidebarTitle: 'Data validation'
description: 'How Nango helps you with data validation for your integrations'
---

All inputs and outputs of [Functions](/guides/platform/functions) are strictly typed.

This allows Nango to help you with automatic data validation for your integrations.

## Built-in data validation

Inputs and outputs of [Functions](/guides/platform/functions) are defined with zod models.

[Zod](https://zod.dev/) is a very popular data validation package for TypeScript.

Nango also automatically generates a [JSON Schema](https://json-schema.org/) definition of your zod models. This makes it easy to generate types for many different programming languages.

Data validation is enabled by default:
- During local development, Nango's CLI will log type errors as warnings
    - You can optionally fail on type errors with a CLI flag

Refer to our [data validation implementation guide](/implementation-guides/building-integrations/data-validation) for more details.
